• Journal of Electrochemical Science and Technology
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• 제12권4호
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• pp.440-452
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• 2021

Enhancement of durability and reduction of maintenance cost of concrete, with the implementation of various approaches, has always been a matter of concern to researchers. The integration of pozzolans as a substitute for cement into the concrete is one of the most desirable technique. Silica fume (SF) and colloidal nanosilica (CS) have received a great deal of interest from researchers with their significant performance in improving the durability of concrete. The synergistic role of the micro and nano-silica particles in improving the main characteristics of cemented materials needs to be investigated. This work aims to examine the utility of partial substitution of cement by SF and CS in binary and ternary blends in the improvement of the durability characteristics linked to resistance for electrochemical corrosion using electrical resistivity and half-cell potential analysis and chloride penetration trough rapid chloride penetration test. Furthermore, the effects of this silica mixture on the compressive strength of concrete under normal and aggressive environment have also been investigated. Based on the maximum compression strength of the concrete, the optimal cement substituent ratios have been obtained as 12% SF and 1.5% CS for binary blends. The optimal CS and SF combination mixing ratios has been obtained as 1.0% and 12% respectively for ternary blends. The ternary blends with substitution of cement by optimal percentage of CS and SF exhibited decreased rate for electrochemical corrosion. The strength and durability studies were found in consistence with the microstructural analysis signifying the beneficiary role of CS and SF in upgrading the performance of concrete.

• 한국재료학회지
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• 제33권9호
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• pp.360-366
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• 2023

This study focuses on how the partial substitution of copper by nickel nanoparticles affects the electrical and structural properties of the Bi₂Ba₂Ca₂Cu_2.9Ni_0.1O_10+δ, Bi₂Ba₂Ca₂Cu_2.8Ni_0.2O_10+δ and Bi₂Ba₂Ca₂Cu_2.6Ni_0.4O_10+δ compounds. Approximate values of crystallization size and crystallization percentage for the three compounds were calculated using the Scherer, modified Scherer, and Williamson-Hall methods. A great similarity was observed in the crystal size values from the Scherer method, 243.442 nm, and the Williamson-Hall method, 243.794 nm for the second sample. At the same time this sample exhibited the highest crystal size value for the three methods. In the examination of electrical properties, the sample with 0.1 partial substitution, Bi₂Ba₂Ca₂Cu_2.9Ni_0.1O_10+δ was determined to be the best with a critical temperature of 100 K and an energy gap of 6.57639 × 10^-21 MeV. Using the SEM technique to analyze the structural morphology of the three phases, it was discovered that the size of the granular forms exceeds 25 nm. It was determined that the samples' shapes alter when nickel concentration rises. The patterns that reveal the distribution of the crystal structure also exhibit clear homogeneity.

• 한국식품영양과학회지
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• 제35권4호
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• pp.487-492
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• 2006

쌀전분에 무수초산을 반응시켜 치환도가 다른 초산 쌀전분들을 제조하여 이들의 이화학적 특성을 비교 검토하였다. % acetyl 함량과 치환도 측정에서 무수초산의 함랑이 증가함에 따라 쌀전분의 % acetyl 함량($0.64{\sim}2.71%$)과 치환도($0.025{\sim}0.104$)는 현저히 증가하였다. Amylose 함량은 초산기의 영향으로 소폭 감소하는 것으로 나타났으며, 원료쌀전분의 팽윤력(24.3 g)과 용해도(8.11%)는 초산 쌀전분(팽윤력 : $29.2{\sim}37.9g$, 용해도. $8.42{\sim}9.55%$)보다 낮았으며, 치환도가 증가할수록 팽윤력과 용해도도 함께 증가하였다. RVA에 의한 호화 특성 측정에서 원료 쌀전분의 최고점도는 4457 cP로 나타났으며, 치환도가 증가할수록 최고점도($4536{\sim}5268cP$)는 증가하였다. 호화개시 온도는 치환도가 증가할수록 낮아지는 것으로 나타났다. 광투과도 측정에서는 초산 쌀전분의 치환도가 증가할수록 광투과도는 증가하는 것으로 나타났다. 주사전자현미경으로 관찰한 원료 쌀전분과 초산 쌀전분의 입자크기는 치환도에 따른 차이를 나타내지 않았다. 전분겔의 이수현상측정에서는 초산 쌀전분의 치환도가 증가할수록 이수현상이 감소하는 것으로 나타났다.

• Asian-Australasian Journal of Animal Sciences
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• 제19권6호
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• pp.779-783
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• 2006

The adiponectin gene is known to be involved in the regulation of energy homeostasis involving food intake, carbohydrate and lipid metabolism. Human adiponectin gene polymorphisms have been recently reported to be associated with obesity, insulin sensitivity and the risk of type 2 diabetes. The present study was carried out to investigate the porcine adiponectin gene as a candidate gene for fat deposition and carcass traits. A mutation of A178G of the porcine adiponectin gene that resulted in substitution of the amino acid Isoleucine to Valine was identified. AcyI PCR-RFLP was used to detect the polymorphism of the genotypes in five different pig populations (Large White, Landrace, Duroc, Chinese breeds Meishan and Qingping). The A allele frequency was significantly higher among subjects from Chinsese lard type breeds, while the G allele was the only one present in those from Western lean type breeds. To determine if there was an association of the polymorphism with phenotypic variation, the mutation was tested in 267 pigs of the "Large $White{\times}Meishan$" F2 resource population. The results of association analyses showed significant associations of the genotypes with fat deposition and carcass traits. Allele G was significantly associated with increase in loin eye height, loin eye area and lean meat percentage and bone percentage, and decrease in fat mean percentage, ratio of lean to fat, shoulder fat thickness, 6-7 rib fat thickness, thorax-waist fat thickness and buttock fat thickness. The substitution of A178G (Ile60Val) happened to be located at amino acid 60 in the collagenous domain of porcine adiponectin which might affect the association into higher-order structures, and accordingly affect the posttranslational modifications and optimal biological activity of the multimeric forms. The identified functional polymorphism provides new evidence of adiponectin as an important candidate gene affecting fat deposition and carcass traits in pigs.

• 한국IT서비스학회지
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• 제19권6호
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• pp.31-53
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• 2020

The traditional media ecosystem is facing major changes with the expansion of over-the-top (OTT) services. While the percentage of people cutting the cord has already exceeded the percentage of people subscribing to pay TV services in the United States, due to the unique characteristics of the Korean market, it is uncertain whether the cord-cutting trend will have an impact on the Korean media industry despite of the advantages of OTT services. Accordingly, this study has directly determined the beneficial and sacrificial factors of switching to OTT services, as well as the personal and external influences behind the Korean OTT service users' intention to switch. To achieve this, the Value-based Adoption Model (VAM) was used to measure the benefits of OTT services with regards to their content and systems, as well as measure the financial and procedural switching costs of cord-cutting; further, personal innovativeness and consumers' social image were added as external variables. The results of this study showed that consumers take the content and system quality of OTT services and procedural switching costs and into consideration, and that their intention to switch was based on social image. These results could serve as data for consumer analysis regarding the expansion of OTT services into the Korean media industry, and also provide the strategic basis for preparing for sudden changes that may occur in the media ecosystem due to cord-cutting.

• Advances in concrete construction
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• 제5권5호
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• pp.437-450
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• 2017

The present work investigates about the development of a novel construction material by utilizing Granulated Blast Furnace Slag (GBS), an industrial waste product, as substitution of natural fine aggregates. For this, experimental work has been carried out to determine the influence of GBS on the properties of concrete such as compressive strength (CS), modulus of elasticity, ultrasonic pulse velocity (UPV), chloride penetration, water absorption (WA) volume of voids (VV) and density. Concrete mixes of water/cement (w/c) ratios 0.45 and 0.5, and incorporating 20%, 40% and 60% of GBS as partial replacement of natural fine aggregate (sand) are designed for this study. The results of the experimental investigation depict that CS of concrete mixes increases with the increasing percentages of GBS. Moreover, the decrease in chloride penetration, WA and VV, and improvement in the modulus of elasticity, UPV, density of concrete is reported with the increasing percentage of GBS in concrete.

• Advances in concrete construction
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• 제10권5호
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• pp.369-379
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• 2020

Reduction of disposal of waste materials due to construction demolition has become a great concern in recent decades. The research work presents the hardened properties of concrete where the partial substitution of recycled coarse aggregate with natural aggregate in amount of 0%, 10%, 30% and 50%. By using different mixed proportions, fresh and hardened properties of concrete were conducted for this investigation. These properties were compared with control concrete. It can be seen that all of the hardened properties of concrete were decreased with the increasing percentage of recycled aggregate in concrete mixes. It was noticed that up to 30% recycled aggregate replacement can be yielded the optimum strength when it used in normal concrete. Finally, it can be said that disposed recycled concrete utilizing as a partial replacement in natural aggregate is a great way to reuse and reduce environmental hazards which achieve sustainability approach in the construction industry.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 추계 학술논문 발표대회
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• pp.157-158
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• 2018

In this study, the current tendency to replace a large amount of material admixture, which is fly ash (FA) and blast furnace slag (BS), into concrete is that high-grade cheese high admixture of high fluidity concrete In consideration of the substitution rate, we considered J-Ring to investigate the influence on the segregation resistance and the method of evaluating the classical segregation. In addition to the admixture replacement rate in the study results, the EIS using J-Ring became lower and the percentage of vehicles with segregation increased. Such a tendency is considered to be positive when J-Ring is used when segregation is judged if segregation degree is similar to EIS using J-Ring.

• 음성과학
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• 제3권
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• pp.38-49
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• 1998

Dysarthrias are a sort of neuromotor disorders because of the weakness of neuromotor controls. They are classified in six types on the basis of Mayo clinic research: flaccid, spastic, ataxic, hypokinetic, hypekinetic and mixed types. Five dysarthria types are investigated in this study. MRI, EMG, neuropathological tests are essential diagnostic processing. Visi-Pitch and Spectrgraphy, CSL are used for assessing dysarthria speech. Maximum phonation time, diadochokinetic rate, Voice Onset Time and substitution rate are the speech evaluation parameters. Maximum phonation time and diadochokinetic rates are the lowest in case of spastic and ataxic dysarthrias. Spastic dysarthria shows the substituted glottalized consonants. However, flaccid, ataxic and hypokinetic dysarthrias show the substituted aspirated consonants. VOT is the longest for hypokinetic dysarthria and the shortest for ataxic dysarthria. Jitter shows higher percentage in comparison with control group. Speech evaluation using experimental phonetic instruments help create on international standardization of speech evaluation for speech disorders.

• 한국세라믹학회지
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• 제30권3호
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• pp.175-180
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• 1993

Influence of Nd3+ substitution for Pb2+ on the dielectric properties and the PbO evaporation according to substituting Nd3+ for Pb2+ in Pb(Mg1/3Nb2/3)O3 system ceramics have been investigated. The dielectric constant at the curie temperature and evaporation of PbO were decreased with increase of Nd3+ amounts. The percentage of PbO evaporation was 2.5wt% in the PMN system substituted Nd3+ for Pb2+, while it was 3.7wt% in the PMN system.